Apparatus for cementing wells



Petented Aug. 17, 1943 APPARATUS FOR CEMENTING WELLS John w. Botkin, Nocona, Ten, asslgnor to Halliburton Oil Well cementing Company, Duncan,

Okla.

Application April 21, 1941, Serial No. 389,536

1 Claim.

This invention relates to apparatus adapted for use in cementing oil wells and more particularly to means for forcing cement through perforations in the casing in a well.

In the cementing of oil wells it is common practice to perform what is known as a "squeeze job. By this is meant that a cement; slurry or other sealing fluid is forced or squeezed by pressure into or against a permeable formation or through perforations in casing and liners for the purpose of shutting off water or reducing gas-oil ratio or for other purposes.

The apparatus of the present invention is adapted to be used for squeeze jobs through perforations and in certain respects may be regarded as an improvement or modification oi. the apparatus of the following U. S. applications and patents:

Patent to Erie -P. Halliburton, No. 2,235,318, for Apparatus for cementing wells, granted March 13, 1941.

Patent to A. D. Stoddard, No. 2,274,940, for

Squeeze cementing of wells," granted March 3,

Patent to S. R.'Robinson-et al., No. 2,239,295, for Cementing tool, granted April 22, 1941.

Patent to S. H. Robinson, No. 2,239,296, for Cementing tool, granted April 22, 1941.

Patent to n. F. Boggs et al., No. 2,244,354, for Cementing tool, granted June 3, 1941.

Application of M. M. Verheul et al., Ser. No. 335,494, filed May 16, 1940, for Apparatus for introducing fluid into an opening.

Application of W. R. McClendon, Ser. No. 3'70,- 190, filed December 14, 1940, for "Removable packers.

As mentioned in some of these applications, in squeeze cementing it is customary, and usually desirable, to fix and seal a tubing or other conduit to the casing above the point where the cement slurry is to be squeezed. For this purpose slips and a packer are utilized. The Stoddard application and the McClendon apparatus are of this type.

In many cases, oil well casing has been perforated opposite a number of formations at different levels and then later it is desirable to squeeze cement into one or another of these formations. It is then necessary to set packers both above and below that set-of perforations.

In the arrangements of the prior art, bridge plugs and cement retainers have been used for this purpose, and more recently, as exempliiied by the art cited above, it has been proposed to provide removable equipment for this purpose.

In accordance with the present invention, it is proposed to provide cementing equipment for the purpose mentioned, and like uses, in which the lower or bridge forming packer is detachable irom theremainder of the assembly, so that it may be set and left in the well to be drilled up when the well is completed.

In some cases this presents considerable ad vantages over prior known arrangements. It avoids the limitation as to fixed spacing between the upper and lower packers common to certain of the prior systems, and thus permits greater flexibility of use. 0n the other hand it eliminates the difiiculties of drilling up large bodies of iron and rubber, experienced when the old types of cement retainers were used.

Accordingly, it is one object of the present invention to supply a bridge plug which may be run in connection with a removable packer and be set below perforations in a casing through which cement is to be squeezed.

It is another object 01' the present invention to provide a bridge plug which may be run in connection with a removable packer to be used in squeeze cementing, said bridge plug being easy to set and easy to detach from a removable packer assembly after said plug is secured to the walls of the casing.

Another object of this invention is to provide a bridge plug which may be run in an oil well on the same trip that the removable packer is run into the well to perform a squeeze job, thus eliminating the necessity of an additional round trip of the tubing, which is a considerable saving of both time and expense. Another object is to provide a novel combination of packers and cementing equipment for wells in which one packer may be set and another moved upwardly therefrom any desired distance, so that cement may then be squeezed in between the two.

Other objects and advantages of this invention reside in certain novel features of the arrangement and construction of the parts, as will partly in cross-section of apparatus constructed in accordance with the invention, the parts being shown in the position they occupy as the apparatus is being lowered into the well;

' Figure 2 is a similar view of part of the asable packer above the said perforations; the apmratus now being ready to perform a squeeze Job.

Referring to the drawing in detail, it will be seen that an oil well casing. is illustrated at M, this being provided with perforations i2. 'Within this casing is a string of tubing, the lower end of which is shown at 53. To this tabing is connected an apparatus for securing and sealing the tubing to the casing. For purposes of illustration, the apparatus shown here is a removable packer similar to the one described and claimed in the co-pending application of W. R. McClendon, Serial No. 370,190, mentioned above. Releasably secured to the lower end of the apparatus is a bridge plug which constitutes a particular feature of the present invention, as

- described hereinafter.

As herein show-n, the removable packer assembly includes a slip body M carrying slips l5, the latter being mounted for limited radial movement in a recess contained in the slip body. Inserted in these recesses behind the slip are slip pads if: made of rubber reinforced with fabric. The slip pads act as packing rings so that by pumping fluid through ports ii in the slip body, the slips are pumped out like a piston until they engage the walls of the casing H. Spring i9 bolted to the slip body l8 provide means for holding the slips E5 in position and for urging them back into the slip body.

A mandrel 253 is threaded into the lower end of the slip body i i and it carries two flexible swab cups 2i directed downwardly as illustrated. The swab cups 2! may be made of rubber or fabric and are held in position by thimbles 22 threaded onto the mandrel. Fluid may flow downwardly between the cups and the casing, but not upwardly by them. The lower end of the mandrel 28 is threaded as shown at 23.

To support the slip body M and the mandrel 26, the upper end of the slip body is connected to a safety joint provided with packing 2b and with a left hand back-ofi thread 271.

The safety joint 25 is in turn connected to a circulation sub consisting of a pipe 28, connected to the tubing 83 by a collar and a sleeve 36 provided with packing as shown at 32 and drag springs as shown at 33. An opening 29 in the pipe 28 provides a valve port covered or uncovered by the sleeve 3 l The apparatus so far described is essentially the same as that described in the McClendon application cited above.

In accordance with the present invention a tubular member 3 5 is threaded into the lower end of the mandrel 20. This member M is pro vided with ports 35 and a J slot 35, by which the bridge plug is releasably connected to the mandrel 20. The bridge plug includes a coupling 31 at its upper end, said coupling having a pin 38 therein which rides in the J slot 3'6 and is held therein by a shear pin 39. Coupling 31 is threaded to the upper end of the bridge plug mandrel 40. On this mandrel a flexible cup 4! made of rubber, fabric or the like is carried. This cup is of known construction and is directed upwardly and acts as a packer or swab. Fluid may flow upwardly and by-pass between the cup and casing, but not downwardly thereby in the annular space between the tubing and easing. This cup 4! may be secured to the casing by wedge member 52, which is slidably mounted on the mandrel and by a set of slips 33, the wedge 42 and slips 13 being connected to the mandrel by shear pins dd. There is an abutment shoulder 45 provided for these slips at the lower end of the mandrel 40.

The coupling 3i is provided with an enlarged chamber 36 which acts as a valve cage for the ball All, and the tubular member 34 is provided with 2. depending rod it which holds the ball down, off of its upper seat until the members 3 3 and 31 are separated. After separation, the ball M acts as a back pressure valve. As illustrated, the ball 4? acts as a valve in two directions. As long as the tubular member 3% is in the position illustrated in Figures and 2, fluid may pass in an upwardly direction through the mandrel am, but when fluid tries topass clown wardly therethrough, the ball 47 engages the seat 39 on the mandrel db and prevent the flow of the fluid in a downwardly direction therethrough. 'When the tubular member 34 has been disconnected from the bridge plug and moved upwardly therefrom as illustrated in Figur 3, the ball 4'! acts as a valve in both an upwardly and downwardly direction, it then being possible for it also to engage seat 50 in the coupling 31.

The operation of the tool illustrated will be apparent from the following example given by way of illustration. Assuming that the operator wishes to carry out a squeeze cementing operation through perforations H2 in the casing H, the procedure may be as follows:

The apparatus is lowered into the hole with the parts as shown in Figure 1. As it is lowered, part of the fluid in the hole will flow upwardly through the bridge plug and part will flow upwardly around the bridge plug, through the ports 35 and through the removable packer assembly. The ports 29 in the circulation sub are also open at this time, so that all the swab cups are by-passed. When the tool reaches the position shown in Figure 1, that is, when the bridge plug and the cups on the removable packer are below the perforated section which is to be squeezed, the removable packer and bridge plug are set by raising the tubing slightly to cause the sleeve 39 to cover the ports 29, and applying pump pressure. When the pump pressure is applied the ball 41 engages the seat ifi and thus confines the pressure between the bridge plug and the removable packer. Fluid is forced out through the ports 35 and pressure is applied to the cup ll. As this pressure is exerted downwardly on the cup, the pins Q4 shear and the slips #3, Wedge t2, and cup 4i take the position shown in Figure 2, so as to fix the cup 4i and mandrel M] to the casing.

As an alternative method of operation, the bridge plug may be set by merely lifting up on it, thus allowing the hydrostatic pressure, due to the fluid above the cup ll to shear the pins 44, instead of shearing them by pump pressure.

After the bridge'plug has taken the position shown in Figure 2 it may be disconnected from the removable packer by liftin up the tubing to shear the pins 39 and rotating the same to the left until the pin 38 isturned out of the Jslot 36. The removable packer may then be moved up the well until it is above the perforations l2, as shown in Figure 3, where it is in position to perform a squeeze job by forcing cement down through the assembly and discharging the same through the member 34. As cement is discharged and forced through the perforations, the bridge plug prevents flow downwardly in the well.

The operation of the removable packer assembly is the same as described in the McClendon application mentioned above. The tubing can be raised or lowered to control the sleeve valve 3| to circulate mud or other fluid in advance of the cement, or after the cement has been deposited to remove any excess. With the valve 3| closed, pump pressure temporarily sets the slips l5 and holds the cups 2| in position so that no fluid can flow upwardly through the annular space between the tubing and easing above the perforations [2.

After the squeeze job has been completed the removable packer may be removed from the bore of the well, and the bridge plug may be left in the bore of the well as a permanent plug, or since the mandrel, slips, packer and associated parts of the bridge plug are made of drillable material, they may be drilled up during the process of completing the W811, thus leaving the bore of the well unobstructed.

Only one embodiment has been illustrated and described herein but it is obvious that the inven' ,tion may be carried out in a wide variety of ways and may be adapted to various than those mentioned.

Materials other than cement may be used as a sealing fluid. The apparatus can also be used for acidizing oil wells. Various changes may be made in the arrangement or construction of the parts without departing from the spirit of the invention or the scope of the annexed claim.

I claim:

Apparatus adapted for use in squeeze cementing through perforations in casing in a well, comprising a conduit, a circulation sub operable by manipulation of said conduit to connect the interichto the exterior of said conduit if desired, a back-off safety joint in said conduit below said circulation sub, a packer assembly secured to said conduit beneath said safety joint and adapted to be removed from the well with said conduit, a bridge plug located beneath said packer assembly and adapted to be fixed to the casing, said bridge plug having means associated therewith for setting the same hydraulically, and means temporarily securing said bridge plug to said packer assembly.

purposes other JOHN W. BOTKIN. 

